Isner withdraws from Australian Open

Sydney, Australia (Sports Network) - American John Isner has pulled out of the
Australian Open due to a right knee injury.

Isner's knee hampered him in his loss to Ryan Harrison at the Sydney
International tennis event, a final Australian Open tune-up.

The big-serving 27-year-old was the top seed in Sydney. He said after
Wednesday's 6-4 6-4 loss to Harrison that he was thinking about pulling out of
the year's first grand slam due to the injury.

"I have been feeling some discomfort in my knee and have recently learned that
I have a bone bruise," Isner said in a statement released by Australian Open
organizers on Thursday. "Doctors have told me that continuing to play on the
knee could result in a more serious injury."